Developing identifiable latent fingerprints from human skin has been a constant frustration to police examiners for a number of years. Past research has been unable to develop a reliable technique for fingerprinting the skin of cadavers.
Many murder victims have had useable latent prints on their bodies but existing techniques failed to recover them for use in identifying any suspects. Generally, the attempts using techniques of the prior art give results between no results and an outline of the fingers or hands.
In the prior art, a number of methods of developing fingerprints have been disclosed. The purpose of most of these methods is to permit fingerprints to be visually displayed on an object without disturbing the fingerprint by means of the development procedure. Many of the prior art methods require that the fingerprints be brushed with a powder or soaked in a solution or otherwise dealt with in a manner which might smudge or harm the latent fingerprints to be developed.
The most commonly used technique for developing latent fingerprints is the dusting method which involves covering a surface or object with a fine powder such as ground carbon or pumice. Other methods for developing latent fingerprints include treating a surface with the chemical ninhydrin; however, this chemical is difficult to use and is highly explosive. Still other methods for developing latent fingerprints include the fuming of objects with iodine gas, and the dipping of objects in silver nitrate. These methods are relatively messy, the developed fingerprints fade quickly, and surfaces of the objects on which latent fingerprints are sought may be damaged. Laser light can be used to expose and outline fingerprints. However, it is inconvenient and expensive to use as it requires a relatively heavy Argon ion laser unit.
Many apparatus have been developed for dealing with the problem of rendering latent fingerprints on objects detectable. However, it has been difficult to apply such techniques to render latent fingerprints detectable on human skin.
It is often necessary, for example, in the case of a murder victim, to render latent fingerprints detectable upon the skin of a victim. Often such victims are not discovered for days or even weeks after the crime and detection of the fingerprints is quite difficult.
Several references in the prior art teach the use of cyanoacrylate vapors for treating objects such that latent fingerprints become detectable upon treatment with appropriate dusting powders. However, the methods of these references are often time consuming, taking upwards from 12 hours to render a latent fingerprint detectable. In addition, the systems disclosed in these references are often inappropriate for use with fingerprints on human skin. Such systems require the immersion of an object in the vapors of the cyanoacrylate for long periods of time. This is often difficult in the case of human bodies.
Therefore, it is an object of the present invention to provide a method and apparatus for rendering latent fingerprints on human skin detectable in a period of time less than one minute.
It is another object of the invention to provide an apparatus which is sufficiently portable such that the apparatus may be easily transported to and from a crime scene for use in rendering latent fingerprints on skin detectable.
Further study of the specification, Figure and Example will lead the practitioner to additional objects and advantages of the present invention.